In my U.S. Pat. No. 6,783,754, Plant-Based Non-Toxic Sunscreen Products (incorporated herein by reference in its entirety), I disclosed plant-based non-toxic sunscreen preparations using cyanins derived from plants. Since the issuance of that patent, a variety of research studies have been conducted (including one self-funded university study) validating the efficacy of cyanins, particularly anthocyanins derived from fruit, in the role of a sunscreen, without toxicity to healthy skin cells. Such studies have been conducted using in vitro human skin cells, in vivo animal skin cells, and in vivo human skin cells.
During that same period, a variety of research studies have been conducted confirming that conventional sunscreens, using regulatory-approved organic- and mineral-based active ingredients, under many conditions are toxic to human skin cells. Some may be also be absorbed into the body and cause systemic illness. In addition, it has been shown that these same ingredients, when released into the environment, damage sensitive ecosystems, particularly marine ecosystems, including destruction of coral reefs.
While the role of cyanins in plants remains in debate, evidence has being gathering that they are involved in UV protection. Speculation includes their roles as an attenuator of UV energy, coupled with some sort of DNA repair mechanism. The effects of both mechanisms of UV protection appear to be concentration related.
To enjoy widespread consumer acceptance, skin preparations used for UV protection must meet certain cosmetic requirements (the look and feel), much of which is somewhat subjective. A classical example is that of zinc oxide. In its natural form, the white skin coloration is considered unacceptable, leading to the necessity to use micronized and nanoparticle versions of the compound.